From 3232985713579510746 X-Google-Thread: f78e5,f6130266038a8c4d X-Google-Attributes: gidf78e5,public X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news1.google.com!news2.google.com!proxad.net!fr.ip.ndsoftware.net!216.196.110.149.MISMATCH!border2.nntp.ams.giganews.com!border1.nntp.ams.giganews.com!nntp.giganews.com!mephistopheles.news.clara.net!news.clara.net!wagner.news.clara.net!194.159.246.34.MISMATCH!peer-uk.news.demon.net!kibo.news.demon.net!news.demon.co.uk!demon!stump.algebra.com!devnull From: ben04_01@freenet.de (Ben Strasser) Newsgroups: comp.std.c++ Subject: Re: Private Methodes declared outside of the class Date: Thu, 19 Aug 2004 18:39:09 GMT Lines: 32 Sender: mail2news@demon.net Approved: fjh@cs.mu.oz.au (Fergus Henderson , moderator of comp.std.c++) Message-ID: <2oj8udFbd9r0U1@uni-berlin.de> References: <2oblfaF8nds3U1@uni-berlin.de> NNTP-Posting-Host: news.news.demon.net Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Trace: news.demon.co.uk 1092940756 10357 158.152.254.254 (19 Aug 2004 18:39:16 GMT) X-Complaints-To: abuse@demon.net NNTP-Posting-Date: Thu, 19 Aug 2004 18:39:16 +0000 (UTC) X-Robomod: STUMP, ichudov@algebra.com (Igor Chudov) X-User-Agent: Mozilla Thunderbird 0.7.3 (Windows/20040803) X-Spam-Checker-Version: SpamAssassin 2.64-mulga_r1 (2004-01-11) on mulga.cs.mu.OZ.AU X-Orig-X-Trace: news.uni-berlin.de G5+2sCVcd4EMMiX5nRirPAVFepnUMeXoncTqpyqBtbgD7t4/Ur X-Spam-Status: No, hits=-4.2 required=5.0 tests=BAYES_00,FROM_ENDS_IN_NUMS autolearn=no version=2.64-mulga_r1 X-Accept-Language: en-us, en X-Received: (from fjh@localhost) by mulga.cs.mu.OZ.AU (8.12.10+Sun/8.12.9/Submit) id i7JId9VK027084; Fri, 20 Aug 2004 04:39:09 +1000 (EST) X-Path: comp-std-cpp-robomod!not-for-mail X-Delivered-To: std-c++@ucar.edu X-Authentication-Warning: mulga.cs.mu.OZ.AU: fjh set sender to devnull@stump.algebra.com using -f X-Newsgroups: comp.std.c++ Xref: g2news1.google.com comp.std.c++:1865 Steve Clamage wrote: > If you could declare member functions outside the class definition, > anyone could hijack the class (for good or bad purposes), or break the > class invariants without anyone knowing. No, you can't if you can only declare private methods outside of the class as I already explained. You can declare and define a private method anywhere but only call it from a public/protected method which is part of the interface an therefor has to be declared in the class. A hacking function which can not be called is no danger. And even if it was possible if the user of the class knows it's data member (even if they are private) he can access them from anywhere using some pointer casts and assuming the internal representation of the class. So you will have to use pImpl or C's handle approach if you really want to stop people from breaking in. Andrei Alexandrescu > What works against information hiding is that lookup precedes > protection check. That arguably is a good thing, but in C++ > you can't easily define a member function that's just totally > "hidden". Why not? I don't see a syntactical problem, I don't see a technical problem, I don't see a risk of breaking encapsulation. --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.jamesd.demon.co.uk/csc/faq.html ]